1. Field of the Invention
The present invention generally relates to data base management systems and more particularly relates to enhancements for providing an interface between a legacy data base management system and Internet servers employing XML (extensible markup language) protocol.
2. Description of the Prior Art
Data base management systems are well known in the data processing art. Such commercial systems have been in general use for more than 20 years. One of the most successful data base management systems is available from Unisys Corporation and is called the MAPPER→data base management system. The MAPPER system can be reviewed using the MAPPER User's Guide which may be obtained from Unisys Corporation.
The MAPPER system, which runs on proprietary hardware also available from Unisys Corporation, provides a way for clients to partition data bases into structures called cabinets, drawers, and reports as a way to offer a more tangible format. The MAPPER data base manager utilizes various predefined high-level instructions whereby the data base user may manipulate the data base to generate human-readable data presentations. The user is permitted to prepare lists of the various predefined high-level instructions into data base manager programs called “MAPPER Runs”. Thus, users of the MAPPER system may create, modify, and add to a given data base and also generate periodic and aperiodic updated reports using various MAPPER Runs.
However, with the MAPPER system, as well as with similar proprietary data base management systems, the user must interface with the data base using a terminal coupled directly to the proprietary system and must access and manipulate the data using the MAPPER command language of MAPPER. Ordinarily, that means that the user must either be co-located with the hardware which hosts the data base management system or must be coupled to that hardware through dedicated data links. Furthermore, the user usually needs to be schooled in the command language of MAPPER (or other proprietary data base management system) to be capable of generating MAPPER Runs.
Since the advent of large scale, dedicated, proprietary data base management systems, the Internet or world wide web has come into being. Unlike closed proprietary data base management systems, the Internet has become a world wide bulletin board, permitting all to achieve nearly equal access using a wide variety of hardware, software, and communication protocols. Even though some standardization has developed, one of the important characteristics of the world wide web is its ability to constantly accept new and emerging techniques within a global framework. Many current users of the Internet have utilized several generations of hardware and software from a wide variety of suppliers from all over the world. It is not uncommon for current day young children to have ready access to the world wide web and to have substantial experience in data access using the Internet.
Thus, the major advantage of the Internet is its universality. Nearly anyone, anywhere can become a user. That means that virtually all persons are potentially Internet users without the need for specialized training and/or proprietary hardware and software. One can readily see that providing access to a proprietary data base management system, such as MAPPER, through the Internet would yield an extremely inexpensive and universally available means for accessing the data which it contains and such access would be without the need for considerable specialized training.
There are two basic problems with permitting Internet access to a proprietary data base. The first is a matter of security. Because the Internet is basically a means to publish information, great care must be taken to avoid intentional or inadvertent access to certain data by unauthorized Internet users. In practice this is substantially complicated by the need to provide various levels of authorization to Internet users to take full advantage of the technique. For example, one might have a first level involving no special security features available to any Internet user. A second level might be for specific customers, whereas a third level might be authorized only for employees. One or more fourth levels of security might be available for officers or others having specialized data access needs.
Existing data base managers have security systems, of course. However, because of the physical security with a proprietary system, a certain degree of security is inherent in the limited access. On the other hand, access via the Internet is virtually unlimited which makes the security issue much more acute.
Current day security systems involving the world wide web involve the presentation of a user-id and password. Typically, this user-id and password either provides access or denies access in a binary fashion. To offer multiple levels of secure access using these techniques would be extraordinarily expensive and require the duplication of entire databases and or substantial portions thereof. In general, the advantages of utilizing the world wide web in this fashion to access a proprietary data base are directly dependent upon the accuracy and precision of the security system involved.
The second major problem is imposed by the Internet protocol itself. One of the characteristics of the Internet which makes it so universal is that any single transaction in HTML (or XML) language combines a single transfer (or request) from a user coupled with a single response from the Internet server. In general, there is no means for linking multiple transfers (or requests) and multiple responses. In this manner, the Internet utilizes a transaction model which may be referred to as “stateless”. This limitation ensures that the Internet, its users, and its servers remain sufficiently independent during operation that no one entity or group of entities can unduly delay or “hang-up” the communications system or any of its major components. Each transmission results in a termination of the transaction. Thus, there is no general purpose means to link data from one Internet transaction to another, even though in certain specialized applications limited amounts of data may be coupled using “cookies” or via attaching data to a specific HTML screen.
However, some of the most powerful data base management functions or services of necessity rely on coupling function attributes and data from one transaction to another in dialog fashion. In fact this linking is of the essence of MAPPER Runs which assume change of state from one command language statement to the next. True statelessness from a first MAPPER command to the next or subsequent MAPPER command would preclude much of the power of MAPPER (or any other modern data base management system) as a data base management tool and would eliminate data base management as we now know it.
Providing the system with the capability to save the needed information from transaction to transaction permits applications to be developed for a true dialog-type interface between the legacy data base management system and an Internet terminal. However, to make maximum use of the database management system from the Internet terminal, an appropriate customized user interface is required. With previous systems, the user interface was predefined in accordance with the related Internet connection.
An especially troublesome issue associated with implementation of communication between the Internet servers and the legacy data base management system involves the XML (extensible markup language) format. The enhanced flexibility of this protocol makes interface with an inherently incompatible format particularly difficult.